Leer



O m 000000000 000000000000 E 000000000 000000000000 W 000000000000000000000 l I 000000000 00000000000? I 000000000 0000000000 0000000000 000000000000 7000000000 000000000000 000000000 000000000000March 10, 1936.

Patented Mar. 10, 1936 S ATENT OFFICE LEER Application January 30, 1935,Serial No. 4,061

7 Claims. (01. 49-47) My invention relates to leers such as are emshowsa modification of a portion of the strucployed in the annealing ofglassware and the ture of Fig. 1.

like, and more particularly to a means for heating the same.

It is common practice to heat leers by gas or oil In some instances,these burners discharge through the side walls of the leer at pointsabove the plane of travel of the Ware being treated, while in otherinstances, the burners are positioned in a burner chamber beneath theline of travel of the ware, adjacent to the entrance burners.

end of the leer chamber.

through the roof, to exhaust stacks.

arrangement, the glassware has no direct contact with the burned gases,and thereby clouding or glooming of the glassware by the gas fumes isavoided, but such structures are somewhat inemcient in that there isconsiderable loss of heat. Also, in many instances, it has been foundnecessary to provide fans for effecting a forced circulation, throughthe various side wall passages, in order to effect proper distributionof the heat.

My invention has for its object the provision of a simplified andimproved method and apparatus for heating leers and the like, in suchmanner that the various objectionable features abovereferred to areavoided.

One object of my invention is to provide an improved means fordistributing heat from burners in such manner that a leer belt will notbecome so unevenly heated as to cause it to become distorted or certainportions thereof unduly elongated relative to other portions, and henceto maintain it in a flatter condition, and to avoid deflection thereoffrom its proper path of travel through the 1eer chamber.

Still another object of my invention is to provide improved guiding anddriving means for a leer belt.

Some of the forms which my invention may take are shown in theaccompanying drawing wherein Figure 1 is a longitudinal sectional viewof a leer structure; Fig. 2 is an enlarged view, taken on the line 11-11of Fig. 1; Fig. 3 is a sectional plan view thereof; Fig. 4 is anenlarged view, taken on the line IV-IV of Fig. 1, and Fig. 5

The leer chamber 5 may be of somewhat the usual form and provided withheat-insulating walls. A leer belt or conveyer 6 preferably of the wirefabric or mesh type, is also provided, for conveying glassware or otherarticles through the leer chamber, and this may be mounted and driven,and adjustably tensioned in any wellknown manner.

The leer chamber has communication with a main stack or flue 1, throughbranch flues 8, 9 and Ill. The flues 8, 9 and ID are provided withsuitable dampers which may be individually adjusted to control flow ofhot gasesfrom the leer chamber. If the 1eer chamber becomes too hot atpoints in advance of the flue III, the dampers 8 and 9 can be opened tothe desired degree to permit exhaust of the heating gases, and thedamper of flue H] can be opened or closed to any desired degree,determined by the temperature conditions in the leer chamber, and inaccordance with well- -known practice. The damper in flue I can, ofcourse, be operated to control flow from all of the flues 8, 9 and Ill.

Vertically-adjustable baffle plates II, l2 and [3 are provided tocontrol the flow of heated gases along the roof or top wall of the leerchamber, so that the heat will not pass off too quickly, and so thebafiling effect on the air will cause it to be deflected downwardlytoward the conveyer belt. These baffles may extend entirely across theleer chamber, and can be raised and lowered by suitable hand-operatedscrews l3a.

Toward the discharge end of the furnace, I provide shutters I4 and IS inthe top and bottom walls of the 1eer chamber, to permit escape of heatfrom the chamber, and to admit cooler outside air thereto whenever it isfound that the ware is too highly heated when passing the location ofthese shutters. The shutters may be simply metal plates hinged at oneedge to the leer, and may be held open or closed in any suitable manner.

The leer is provided with a burner chamber I! that may be somewhat inthe form of a depression in the bottom wall of the leer chamber. Baffleplates l8 of cast iron or of more refractory material, such as clay,extend transversely of the leer and across the burner chamber. A burnertube l9, provided with a series of gas discharge openings, is mountedbeneath each burner plate it, a mixture of gas and air being supplied toeach of the burner tubes through a gas and air mixer 20. The gas issupplied to each air mixer By this 20 from a gas conduit 2! past acontrol valve 22. Additional or enlarged openings 23 are provided at themixers 20, to admit additional air to the burner chamber so as to insuremore perfect combustion of the gas, and in order to provide suitablenatural draft flow of the hot gas through the leer chamber. Flow of gasthrough the conduit 2| to the mixers 20 is controlled by a valve 24, andthis valve may be automatically actuated in accordance with temperatureconditions in the leer chamber in any wellknown manner, as by means of athermostatic device 25.

The bafile plates l8 may be of sufficient thickness toabsorb aconsiderable amount of heat, so that when the burner flame is reduced orcut off entirely, they will radiate heat to the underside of the belt 6,thus assisting in maintaining uniformity of temperature and avoidingquick changes in temperature within the leer, through fluctuations inflame intensity. The plates may suitably be one inch or greater inthickness.

An important feature of my invention resides in the provision ofperforations in the plates l8 and the spacing thereof throughout theplates. As shown in Fig. 3, the center-to-center spacing of theperforations in the plates 18 gradually decreases from the axial centersof the plates to the marginal edges thereof in longitudinal andtransverse directions. Also, the perforations are of graduateddiameters, those disposed adjacent to the edges of the plates being ofgreater diameter than the perforations located adjacent to the axialcenter of the plates. By this arrangement, heat from the burners I9 isuniformly distributed throughout the length and width of the conveyerbelt and the ware carried thereby over the combustion chamber.

For example, the perforations may be of diameters graduated betweenone-fourth inch and one-half inch diameter. Likewise, thecenter-tocenter spacing between the perforations may be one and one-half(1 inches adjacent to the axial center line of the plates and graduallydecrease to one inch centers along the marginal edges of the plates.These dimensions, of course, may vary in accordance with particularconditions encountered or desired.

The holes are of such small diameter that the plates will exertsufficient baffling effect on the flames to prevent the flames fromdirect engagement with the ware that is carried on the conveyer belt.Also, they cause a better distribution of the burner heat against thebelt and the ware. It will be seen that if the plates were solid, theheat would mainly pass around the edges of the plates and against thelower side of the belt at somewhat localized areas. Not only would theware thereby be subject to uneven temperatures in passing across theheating chamber I1, but the metallic belt 6 would be so unevenly heatedas to increase danger of warping and shifting thereof.

If some longitudinal portions of the belt are heated to a materiallysmaller extent than other longitudinal portions thereof, there will, ofcourse, be tendency for the belt to shift diagonally or transversely ofits normal path of travel.

Ordinarily, the burner flames will be of such length that they do notquite touch the burner plates I8, thereby reducing danger of incompletecombustion and consequent smokiness of the burnt gases. The plates illwill become heated to red-hot temperature or higher, and therebyfacilitate the complete combustion of the gases, after the manner ofclay radiants employed in gasheating stoves.

The burner plates also shield the ware traveling on the conveyer belt 5from the direct radiation of or contact with the burner flames, so thatthe Ware is protected from excessive heating, and there is less dangerof it becoming clouded by the flames.

The perforated baiile plate arrangement will, of course, be useful alsoin connection with the annealing of sheet glass, which may be pushedthrough the leer simply on rollers, and without the use of a conveyerbelt. The distribution and evenness of the heat on the sheets of glasswill be better by reason of the perforations, as above explained.

The plates 13 may be of considerable thickness, so that they will absorband retain a large amount of heat which will be given off. While thereis gas flame at the burners, the upper sides of the plates will radiateheat against the bottom of the ware as the ware passes over the plates,with the result that there is better uniformity in the application ofheat to the Ware.

Furthermore, in case the valves of the burners' are closed or nearlyclosed, the burner plates will radiate heat to the ware, and prevent toosudden cooling thereof.

Guide rollers 26 and 2'! are mounted adjacent to the front and rear endsof the leer, at points away from the more highly heated zones. Theserollers have idling movement on vertical axes, and may be composed of orfaced with some nonmetallic material such as rubber, or a substance thatwill not readily damage the edges of the metallic belt. The rollers areof such suitable length axially that they will properly guide the belt,even though there is some vertical displacement of the belt duringoperation of the leer.

The belt passes around the usual guide rollers at the entrance end ofthe leer, and at the discharge end thereof, passes around guide rollers28, 29 and 30. A driven roller 3| is provided for driving the belt, theroller being driven in any suitable manner. It Will be noted that thedriving engagement between the roller 3| and the belt is at the innerface of the belt, instead of with the ware-carrying surface thereof.This arrangement reduces danger of the ware-carrying surface of the beltbeing distorted through frictional driving engagement with the roller3|, and hence there is less likelihood of the Ware tilting on the beltbecause of unevennesss in the ware-supporting surface of the belt.

In Fig. 5; I show a modified form of belt drive and guide, wherein whilethe driving roller 33 engages the inner surface of the belt, two guiderollers 34 and 35 are suficient as compared to the three rollers 28, 29and 30. Also, in the form shown in Fig. 5, there is a greater area ofdriving engagement between the roller 33 and the leer belt.

I claim as my invention:-

1. The combination with a leer chamber and means for supporting wareduring movement thereof through the chamber, of a burner disposedbeneath the path of travel of the ware, and. a burner plate interposedbetween the burner and said path, the burner plate having perforationswhich are of less total area in the zone immediately above the burnerthan in the remaining portions of the plate.

2. The combination with a leer chamber and.- means for supporting wareduring movement thereof through the chamber, of burners disposed beneaththe path of travel of the ware, and a burner plate interposed betweeneach burner and said path, the burner plates having perforations whichare of less total area in the zones immediately above the burner than inthe remaining portions of the plates, and the plates being spaced apartin directions longitudinally of the leer.

3. The combination with a leer chamber and means for supporting wareduring movement thereof through the chamber, of burners disposed beneaththe path of travel of the ware, and a burner plate interposed betweeneach burner and said path, the burner plates having perforations whichare of less total area in the zones immediately above the burner than inthe remaining portions of the plates, certain of the edges of the platesbeing unobstructed, to permit upward flow of heated gases past saidedges.

4. The combination with a leer chamber and a ware conveyer therefor, ofburner plates disposed beneath the conveyer and extending transverselythereof, and burners disposed beneath the said plates and approximatelyoo-extensive in length therewith, the plates being laterally spacedrelative to one another, the burner plates having perforations which areof less total area in the zones immediately above the burner than in theremaining portions of the plates.

5. The combination with a leer chamber and a ware conveyer therefor, ofa burner chamber beneath the said conveyer, burner plates disposed inrelatively spaced relation beneath the conveyer, and burners disposedbeneath the said plates, the plates being positioned above the burnersat such height that they are normally out of contact with the burnerflames, the burner plates having perforations which are of less totalarea in the zones immediately above the burner than in the remainingportions of the plates.

6. The combination with a leer chamber and a ware conveyer therefor, ofa burner disposed beneath the conveyer, a heat-absorbing and radiatingmember interposed between the burner and the conveyer, edge portions ofthe said member being unobstructed, and the member being provided withvertically-extending perforations which are of less total area in thezones immediately above the burner than in the remaining portions of theplates.

'7. The combination with a leer chamber and means for supporting wareduring movement thereof through the chamber, of a burner disposedbeneath the path of travel of the ware, and a burner plate interposedbetween the burner and said path, the burner plate having perforationsdistributed throughout the major portion thereof, the perforations inthe zone above the burner being of smaller diameter than theperforations in the other portions of the plate.

EDWARD C. STEWART.

